ol006697a_si_001.pdf (637.2 kB)
Highly Stereoselective Intramolecular Michael Addition Using α-Sulfinyl Vinyllithium as an Unprecedented Michael Donor
journal contribution
posted on 2000-12-05, 00:00 authored by Naoyoshi Maezaki, Sachiko Yuyama, Hiroaki Sawamoto, Tomoko Suzuki, Mayuko Izumi, Tetsuaki TanakaThe first example of an asymmetric intramolecular Michael addition reaction using α-lithiated vinylic sulfoxide as a Michael donor is reported.
Michael addition of the α-lithiated vinylic sulfoxide to (Z)-enoates proceeds with high diastereoselectivity to give the adducts having a stereogenic
center with (R)-configuration at the β-position of the ester in the cyclopentene ring formation. The selectivity was reversed in the six-membered
ring formation. On the other hand, the corresponding (E)-enoates provided Michael adducts with poor diastereoselectivity.